Basic open hearth roof construction



June 4,1963 G. SHAPONA ETAL 3,092,051

BASIC OPEN HEARTH ROOF CONSTRUCTION Filed May 27. 1960 3 Sheets-Sheet 1iLL b' INVENHRS Gear e Sluyvomw y flowaz' delBmzmfz ATTORNEYS June 4,1963 G. SHAPONA ETAL 3,092,051

BY FWMWJ M ATTORNEYS June 1963 e. SHAPONA ETAL 3,0

BASIC OPEN HEARTH ROOF CONSTRUCTION Filed May 27. 1960 3 Sheets-Sheet 3INVEN TORS George Shapozza/a,

By llowa/zvleflBrown '3 ATTORNEYS United States Patent f 3,092,051 BASICOPEN IEARTH ROOF CONSTRUCTION George Shapona, Greenville, and Howard J.Brown, Clark, Pa, assignors to Sharon Steel Corporation, Sharon, Pin, acorporation of Pennsylvania Filed May 27, 1960, Ser. No. 32,204 4Claims. (Cl. 110-99) This invention relates to a roof construction for ametallurgical furnace. More particularly it pertains to a basic brickproof construction for an open hearth furnace.

The use in recent years of basic rather than acid (silica) bricks forthe flame exposed surface of roofs of open hearth furnaces has beenincreasingly desired and many constructions have been proposed and used.Basic bricks ordinarily are composed of rnagnesite and chrome in Varyingproportions. Often they are metal plated or encased and also reinforcedwith internal metal plates to reduce spelling when subjected to elevatedtemperatures (2800 F.3250 R), which was formerly a weakness :of basicbricks. Moreover, wear or erosion of the flame exposed surfaces of openhearth furnace roofs is not uniform. In the ideal construction of anopen hearth furnace all parts should wear out at the same rate so thatonly one shutdown is required for a complete rebuilding of the furnace.

One advantage of a basic roof over an acid roof is that the former canwithstand temperatures of above 3250" F. as compared with a maximum ofabout 3000* F. for an acid (silica) roof without apparent damage. Abasic roof can be heated faster so that the furnace can be put intoproduction sooner. This in part compensates tor the higher cost of basicbrick. Also, the basic roof lasts on the average about twice as long asa comparable silica roof because it is more resistant to the corrosiveeffects of heat and chemical action.

Most of the basic roofs recently proposed are of sprung arch orsprung-suspended construction with varying amounts of suspension rangingfrom almost none to full suspension. In many prior roofs, whethersuspended or unsuspended, a complicated rigid steel superstructure isrequired, not only to hold up the roof, but also to yieldingly hold theroof against the effects of expansion. The intended purpose :of suchprior roof constructions has been to remove stress from the hot face orflame exposed surface of the bricks to prevent spalling.

The conventional procedure for installing most prior basic roofs of thesprung arch type, whether suspended or unsuspended, is to provide woodenforms on which the bricks are placed. Most such roofs use l-beamsrunning from end to end longitudinally of the furnace axis and atdifferent horizontal levels, depending upon the arch, to form the roofcontour. These beams in turn are mounted, sometimes yieldingly, on arigid furnace superstructure. Tie plates are also provided betweencourses of bricks and perpendicular to the l beams at spaced intervals.Frequently the bricks are suspended from the tie plates individually onwire hangers. Moreover, the individual bricks have been notched in somemanner, and thereby weakened, to provide for hanging or suspension.

It has been found, however, that a sprung larch roof having means merelyfor holding up the brick without additional holddown devices has beenunsatisfactory because the basic brick roof expands upwardly when heatedand subsequently collapses. The reason for the ultimate collapse of theroof is that when the roof expands upwardly upon being heated, theweight of the arch, which was originally borne by the bricks, per se, incomplete surfaceto-surface contact with each other, is borne only by thelower edges of the bricks. That is, in the expanded position the upperbrick surface portions move out of complete surface-to-surface contactwith each other, leav- 3,992,51 Patented June 4, 1963 2 ing only thelower edge portions in pinched positions to bear the load of the arch.Ultimately the lower edges yield to the heat and weight and may becrushed, so that the gradual spalling results in collapse of the arch.

The roof construction of the present invention avoids prior difficultiesand utilizes Wedge-shaped, unnotched, metal-encased basic brick. Thebrick casing includes preferably a pair of integral hanger members orhooks by which each brick is hung in place on an overhanging archmember. Bach arch member preferably comprises an al enate-shaped H beam,l-beam, or inverted T beam having a lower flange extending across thetop of the furnace from the front to the rear sides. The hanger membersor hooks for each brick are engaged on and suspended by the lower flangeof one beam. The bricks are placed in side-to-side and course-to-conrseabutment, respectively, with bricks in the same course and in adjacentcourses, to provide the complete basic roof for the furnace. Also, theupper end of each unnotched brick is engaged and held by an arch memberagainst upward movement. That is, each brick is individually anddirectly held down by an arch member as well as being suspended by sucharch member.

'In addition, the ends of each arch member beam are secured in place atopposite sides of the furnace so that the beams not only hold up eachbrick but also hold down each brick to prevent the arch of bricks fromexpanding or swelling upwardly in the prior manner as the roof absorbsheat from the furnace in operation.

The roof construction of the present invention also preferably utilizesmetal fusion plate-s formed of metal of substantially heavier gauge thanthe casing metal for the individual brick. These tfiusion plates alsoare provided with hanger members, books or means which cooperativelyengage the lower flange means of two adjacent arch members or beams.Bach fusion plate preferably has a length from its hanger means to itslower end, equal to the length of any brick from the bnicks hanger meansto its lower end. Each fusion plate also has a width equal to the widthof two bricks and to the spacing between adjacent arch beams or members.

The fusion plates are hung from the opposed flange means of two adjacentarch beams and span the centerto-center distance between the arch beams,and also span the arch course of brick hung from a lower flange at oneside of one beam and the abutting arch course of brick hung from theopposed lower flange at the other side of an adjacent beam. Furthermore,the fusion plates are inserted at intervals along the brick arch coursesbetween say every three or more bricks to accomplish several importantfunctions.

First of all, the fusion plates, in being formed of heavy gauge metaland in being hung from the metal arch beams, provide a path for thedissipation of heat from the roof refractory.

Second, when the improved roof has been erected and the furnace heatedup, some fusion may take place between the fusion plates, the contactingmetal-encased bricks, and the brick refractory to more completelyintegrate the roof.

Furthermore, (as heating within the furnace continues by continuedexposure of the internal surface of the roof to the furnace flame, theflame exposed ends of the brick refractory material may burn 0Esomewhat. At the same time the inner ends of the individual brick metalcasings as well as the fusion plates may burn back further betweenadjacent bricks than the refractory burn-off. This burn-01f or burn-backat the flame exposed surface of the roof is accompanied by arearrangement of the compounds and complex reactions under the highoperating temperatures involved.

Reactions between iron oxide originating from the metal of the brickmetal casings and the metal fusion plates, and the brick refractorymaterial may cause a swelling of the inner ends of the brick at andadjacent the flame exposed surfaces. In prior constructions, suchswelling sometimes resulted in a build-up of crushing pressures betweenadjacent brick which contributed to an increased spalling eifect.

However, the spaces left in the zones where there has been fusion plateburn-back, at the intervals along each course of every three or morebrick where the fusion plates are located, provide spaces for swellingof the flame exposed brick refractory material ends without a build-upof damaging, crushing forces incident to swelling.

One of the outstanding aspects and advantages of the improvedconstruction is that unlike prior constructions it is simple to installand requires a minimum of parts. Inasmuch as each brick is provided withat least one integral hanger member for attaching directly to a fixedsupporting arch beam, rather than being suspended by interconnectingwires, tie plates, etc. of prior constructions, no separate arch formsare required to be installed upon which the improved arched roof iserected. Such forms required by prior constructions must be subsequentlyremoved after the roof is completed. The material and labor installationand removal costs of such temporary arch forms, necessary for erectingarched roofs of prior construction, are thus completely eliminated.Moreover, the encased, unnotched basic bricks used in accordance withthe invention, having integral hanger members or hooks, may be installedreadily by unskilled labor. Thus, skilled brick masons are not requiredto lay up the arched roof, so that an additional cost item iseliminated.

The elimination of forms required by prior constructions for rooferection has a further advantage in accord ance with the invention.Thus, the improved roof may be readily, quickly and easily patched atlow cost where necessary, Without the erection and removal of forms bysimply removing the bricks requiring replacement and hanging new bricksin their place.

With regard to the connecting parts required, each brick used inaccordance with the present invention has its own integral hanger memberor means which is attached directly to the arch-forming beam rather thanindiie'ctly through interconnecting wires, tie plates, etc. as in priorconstructions. As a result, the number of different parts necessary forthe improved construction is maintained at a minimum.

A further aspect of the invention from the standpoint of a reducednumber of parts or elements utilized in the improved construction isthat only two different encased,

unnotched basic bricks are used, namely, a regular brick and a keybrick, each of which has the same wedgeshaped configuration. The onlydifference between the regular and key brick is the location of theintegral hanger means therefor.

Moreover, the arch-forming beams include lower flange means on which thebricks are hung to carry or hold the weight of the bricks. When thebricks are thus hung, the upper ends of the bricks abut the undersurfaceof the flange means so that the bricks also are held down in place incomplete side-to-side abutment with each other. By bolting down theopposite ends of each beam the entire assembly is prevented fromexpanding or heaving upwardly from the furnace heat in operation.

The arch beams are equally spaced at intervals with a spacingsubstantially equal to the width of two bricks. Thus, the bricks in onecourse hung from a lower flange at one side of one beam are in abutmentwith similar bricks in an adjacent course hung from a lower flange atthe other side of an adjacent beam. Similarly, the bricks hung from thelower flange at the other side of said one beam abut with the brickshung from said one side of said one beam; and also abut similar bricksin a third course hung from flange means of a third arch beam. Thebricks thus hung from and held down by the arch beams cooperate tomaintain each brick in complete engagement with its corresponding beamand with each other. Thus, the bricks are in effect key-locked togetherby interengagement with each other and the arch beams.

The described advantages and features of the improved constructioncooperate to achieve further all important advantages and results.Because of the simplicity of the construction, the minimum number ofparts required, and the elimination of form erection and removal, afurnace is only down or out of opeartion about one-half of the timeheretofore required to rebuild a roof. Thus, furnace tonnage can beincreased by the amount of down time saved.

Furthermore, aside from actual brick cost which may be assumed to be thesame for any roof regardless of construction, because of the reducedlabor and materials costs, and because of the time saved in rebuilding,all of which characterize the improved construction, the material andlabor costs for any roof constructed in accordance with the inventionare approximately one-third of similar costs for prior basic open hearthroof constructions.

In addition to the foregoing, the entire roof asembly may be cooled, ifdesired, either by water or forced air passed through conduits formed inthe arch beams, to achieve the benefits accompanying a cooled furnaceroof, including a longer roof life.

Accordingly, it is a general object of this invention to provide a newbasic open hearth roof construction which may be installed readily at aminimum cost and with a minimum number of parts.

it is another object of this invention to provide a new basic openhearth roof construction which includes arch beams at spaced intervalsto which each roof brick is separately attached and by which each archcourse of bricks is held in a permanent, fixed, arched position.

It is another object of this invention to provide a new basic openhearth roof construction including a plurality of spaced arch beams towhich each brick is held fixed by direct abutment between each brick andbeam, and by which each arch course of bricks is held permanently inplace against upward expansion which would otherwise result due to theheat of the furnace.

It is another object of this invention to provide a new basic openhearth roof construction in which the bricks in each arch course areheld down in side-to-side wedge abutment with each other to avoidbreaking and spelling of the brick which could otherwise result from thebrick rising out of abutment and into pinched engagement at their lowerends.

It is another object of this invention to provide a new basic openhearth roof construction utilizing unnotched, metal-encased, basic brichwith integral hanger members by which the brich are individually andseparately secured and held fixed in place on the flange of an arch beamin erecting the roof without the necessity of install ing temporary archforms for roof erection.

It is another object of this invention to provide a new basic openhearth roof construction in which the bricks of one arch course areseparately secured in place on one arch beam and in which the bricks ofan adjacent arch course are similarly secured so that edge abutmentbetween bricks of adjacent courses hold such bricks in place.

It is anoher object of this invention to provide a new basic open hearthroof construction including spaced arch beams which hold each course ofbricks in fixed position by holding up and holding down each arch courseof bricks.

It is another object of this invention to provide a new basic openhearth roof construction in which spaced arch beams are provided withreinforcing tube means by which the furnace roof may be cooled bypassing coolant fluid through the tube means.

Also it is an object of this invention to provide a new basic openhearth roof construction utilizing only two different wedge-shaped,unnotched, metal-encased, preferably internally reinforced, basic roofbrick with lntegral hangers and with hanger location being the onlydifference between the two different brick.

In addition, it is an object of the present invention to provide a newbasic open hearth roof construction in which burn-off of the flameexposed surfaces of the erected roof does not cause excessivedeterioration of the roof, or spalling and dropping out of portions ofindividual brick.

Likewise, it is an object of the present invention to provide a newbasic open hearth furnace roof construction which may be readily andeasily patched with a minimum of time and expense, and which may beerected to rebuild a furnace roof in substantially one-half the elapsedfurnace down time heretofore required in rebuilding basic open hearthfurnace roofs.

Finally, it is an object of the present invention to provide a new basicopen hearth furnace roof construction which accomplishes the foregoingobjects and desiderata in a simple, effective and inexpensive manner.

These and other objects and advantages, apparent to those sldlled in theart from the following description and claims, may be obtained, thestated results achieved, and the described difliculties overcome, by theapparatus, constructions, arrangements, combinations, subcombinations,elements, parts, and principles, which comprise the present invention,the nature of which is set forth in the foregoing general statements,preferred embodiments of whichillustrative of the best modes in whichapplicants have contemplated applying the principlesare set forth in thefollowing description and shown in the drawings, and which areparticularly and distinctly pointed out and set forth in the appendedclaims forming part hereof.

In the drawings which illustrate the new roof constructiondiagrammatically:

FIG. 1 is a fragmentary perspective view of a roof of an open hearthfurnace constructed in accordance with the invention showing the mannerin which the basic brick are separately attached in place directly toarched support beams;

FIG. 2 is an enlarged fragmentary perspective view showing oneembodiment of the bricks and the manner in which they are assembled;

FIG. 3 is a perspective view of an unnotched, metalencased, wedged basicopen hearth brick of regular construction having metal integral hangermembers and used in the improved roof construction;

FIG. 4 is a perspective view of a generally similar key brick havingdifferently located hanger means used to complete and lock each archcourse of brick;

FIG. 5 is a perspective view of a fusion plate which is installed atspaced intervals of three or more bricks in each course and spanning twoadjacent courses;

FIG. 6 is a fragmentary perspective view showing the manner in which thekey bricks are locked in place in the various arch courses;

FIG. 7 is a diagrammatic view showing the manner in which a watercoolant system for the roof may be in stalled in conjunction with -acoolant system for furnace doors and door frames;

FIG. 8 is a plan view showing the manner in which the ends of adjacentarch beams are bolted in place;

FIG. 9 is a vertical sectional view taken on the line 99 of FIG. 8; and

FIG. 10 is a fragmentary elevational view of a portion of the flameexposed ends of the roof brick after some burn-off has occurred.

Similar numerals refer to similar parts throughout the several figuresof the drawings.

In FIG. 1 a roof 1 is generally indicated as a basic roof for an openhearth furnace in conneciton with which the invention will be describedin detail. However, it is understood that the improved construction maybe used for the roof of any other metallurgical furnace. The roof 1includes a plurality of adjacent arched courses 2 of bricks 3. Eachcourse of bricks includes a plurality of similar regular wedge bricks 3which are separately attached to an arched support beam 4. A pluralityof beams 4 are disposed at longitudinally spaced intervals across thetop of the furnace roof 1 and have ends secured at front and back wallsin a similar manner.

For example, as shown in FIG. -l, the courses 2 of bricks 3 rest uponskew brick 5 which rest upon a front wall 6 and similarly on the backwall (not shown) of the furnace. In addition, the lower front ends ofthe arched beams 4 are fixedly attached to the upper flange 7 of achannel member 8 above the skews 5. The bricks 3 in courses 2 aresolely, individually, and directly supported by the spaced beams 4 anddo not depend upon any other furnace supporting or reinforcing memberfor their support, such as furnace superstructure 9.

As shown in FIG. 3, each regular brick 3 is composed of a solid,unnotched block, internally plated or reinforced if desired, ofrefractory material 10, such as magnesite, contained within a metalcasing -11 on the sides 11a and edges 11b of the brick. The upper andlower ends of the brick as shown are not encased. In addition, thecasing 1 1 is provided with two hanger members or hooks 12 projectingupward from the sides 11a of the brick, which are preferably integralwith the casing 11. However, the hangers 12 may be separate metal piecessecured to the casing as by welding, where the hooks 12 cannot befabricated readily as integral parts of the casing 11.

The brick 3 has a wedge shape with the upper end between sides 11athicker than the lower end so that when placed together the bricks formthe arched courses 2 as shown in FIG. 1. Although the bricks 3 arepreferably provided with two hooks as shown in FIG. 3, the bricks mayinclude only one hook 12, such as shown in FIG. 1. Two hooks '12 arepreferred to enable placement of each brick 3 in a balanced position onthe beam 4 although one book is suflicient for holding a brick in placeThe manner in which the bricks 3 are attached to .the arch beams 4 ismore particularly shown in FIG. 2, in which each beam 4 is composed of atubular member or pipe 13 having an inverted T-beam 141 secured to theundersurface of the member '13, such as by welding. In the alternative,the beam '4 may comprise an H- or I- beam preformed to the radius of thedesired arch.

In FIG. 2 each regular brick 3 is secured by the hooks 12 to a flange 15extending from one of the opposite sides of the axis of the beam 4. Inthat manner the bricks in adjacent courses abutting each other betweeneach pair of beams 4 hold each other in place to prevent them fromslipping out of hooked engagement with the flanges 15. A new roof ispreferably installed by inserting the bricks in the space between thebeams 4 and engaging the hooks 12 over a flange 15 as shown in thedrawings.

Installation of each course of bricks starts from opposite skews ofwhich only the front skew 5 is shown, and continues upwardly to thecenter of the arch where, because of space limitations, one or more keybricks 16 (FIG. 4) are placed. The Wedge key brick 16 is similar in allrespects to the regular wedge brick 3 except that the key brick isprovided with a single hanger member or hook '17 extending upwardly fromone edge 11b of the brick rather than from one or both sides 11a of thebrick 3, as shown in FIG. 3. By such construction the key brick 16 maybe laterally inserted into place without the necessity of sliding thekey bricks both longitudinally and transversely of the beams 4 as isnecessary for hanging the wedge bricks 3 in place. With the regularWedge brick 3 additional room is needed for inserting the bricklaterally to engage the hangers 12. with a beam flange 15 and thensliding the hooks 12 into place along flange 15.

However, the key bricks 16 may be inserted by sliding laterally intoplace and when in place a short rod 18 is inserted beneath the books 17with opposite end portions of the rod resting upon the flanges 15 ofadjacent beams 4. As shown in FIG. 1, a number of key bricks 16, such asthree or more, may be installed in each arch course, preferably at thecenter or uppermost portion of each course 2 of bricks.

Each course 2 of bricks is provided with a plurality of fusion plates 19which are situated as shown in FIG. 1, at spaced intervals preferably ofthree bricks, although any desired fusion plate spacing may be used,depending upon the furnace design, size, operating conditions, etc.

The fusion plate 19 preferably includes a lower rectangular portionwhich is disposed between the bricks 3, having a length equal to thelength of the brick 3 and a width equal to the width of two bricks 3. Inaddition, the plate 19 includes an upper fin portion 20 of substantialarea separated from the lower portion of the plate by oppositelyinwardly extending siots 2.1. The fin portions above the slots serve asbooks for engaging oppositely disposed flanges I15 of two adjacent beams4 (FIG. 2). The fusion plates 15 are formed of much heavier gauge metalthan the gauge of the brick casing metal. Thus the thick fusion plates19 conduct heat outwardly from the bricks to the fin portions 20 andarch beams 4 which dissipate the heat into the atmosphere above theroof.

The plates 19 also serve a purpose of facilitatiing expansion of flameexposed ends of the brick 3 by minimizing the effect of such expansion.As shown in FIG. 10, the bricks 3 when the roof is erected have originallower flame exposed end surfaces indicated by the dot-dash line 22.After the furnace has been heated and in operation at temperatures above3000" F. and usually at 3100- 3250" -F., the flame exposed refractorymaterial ends of the brick 3 may burn oif or burn back somewhat asindicated in full lines in FIG. at 23. At the same time, the inner endsof the individual metal casing for the brick mayburn back further,between adjacent bricks,than the refractory burn-off, as indicated infull lines at 23a in FIG. 10. Similarly, the thicker metal fusion platesmay burn back further than the refractory burn-off, as indicated at 23!)in FIG. '10.

This burn-off or burn-back of both refractory material and metal at theflame exposed surface of the roof is accompanied by a rearrangement ofthe components and complex reactions under the high operatingtemperatures involved.

Reactions between iron oxide originating from the metal of the metalcasings and metal fusion plates and from the furnace atmosphere, and thebrick refractory material may cause a swelling or expansion of theinner, hotter ends of the brick at and adjacent the flame exposedsurfaces, as indicated at 24 in FIG. 10. In prior constructions, suchswelling as well as the high expansion rate of basic brick sometimesresulted in a build-up of crushing pressures between the lower ends ofthe brick longitudinally of each arch course, which contributed to anincreased spalling effect.

However, in the improved construction of the invention, with the heavyfusion plates located as described, the spaces left (see 241: betweendot-dash lines indicating spaces occupied by plates 19 before burn-elf)in zones where there has been fusion plate burn-back, at intervals alongeach arch course of brick, provide space for swelling 24 of the flameexposed and burnt-back brick refractory material ends. Thus there is nobuild-up of damaging, crushing forces incident to swelling or expansionof the refractory at the flame exposed ends of the brick and spallingthereof is substantially reduced, the surfaces fusing to form a hard,efficient, integrated, flame exposed surface.

These swelling and expansion problems encountered in the use of basicbrick for open hearth furnace roofs heretofore have presenteddifliculties that have not been eliminated in prior attempts to provideall-basic brick roofs in metallurgical furnaces, and particularly foropen hearth furnaces where very high temperatures of operation areinvolved.

The roof construction of the present invention solves the long-existingproblems of expansion in an all-basic brick open hearth furnace roof inthe manner described.

Where no means are provided to prevent expansion of an arch course ofbasic brick, as the lower end portions of the brick expand, the brickstend to rise upward, and the upper portions of the brick necessarilymove out of contact with each other, leaving a wedge-shaped spaceusually between each pair of bricks. Simultaneously the entire archcourse heaves upwardly out of its original shape and location. As aresult, the weight 'of the load of the entire arch course is borne byrelatively small end portions of expanded brick which, being weaker atthe higher temperature of operation of the furnace, crack and spell 01?.This process continues until entire bricks drop out and the roofultimately fails.

As shown in FIG. 2, the upper ends of each brick 3 are in flat surfaceabutment with the undersides of the flanges E5 of the l-beams l4; and,as shown in FIGS. 1, 8, and 9,

the opposite ends of the beams 4 are secured by the bolts 25 to thechannel members 8 so that each beam 4 is held in place. Thus it isimpossible for the bricks themselves or the arched courses 2 of bricks 3to rise due to any expansion of the lower end portions of the bricks, aswas the case heretofore in prior basic brick roofs. Thus the bricks areheld in complete surface-to-surface contact between their wedge sideslla with each other.

The fusion plates 19 cooperate with the beams 4 to prevent the archcourses 2 of bricks 3 from heaving or swelling upwardly. As indicated,the lower ends of the fusion plates 1% melt away and recede upwardly ata faster rate than the bricks 3, thereby providing space into which thelower end portions 24 of the bricks may swell or expand.

The beams 4 perform the double function of holding up and holding downeach individual brick. Moreover, if for any reason, one or more bricksshould drop out of place, each of the remaining bricks is held in placeseparately by the hooks 12 as well as by the edge-to-edge abutmentbetween adjoining bricks in adjacent courses.

The beams 4 are each rigid members composed of a durable material suchas steel and each has a shape of a tube over an inverted T-beam as shownin the drawings, or of an H-beam or an l-beam of suitable height. Wherethe beam 4 has the configuration shown in the drawings including atubular member or pipe 13, the beam 3 not only has a rigid structure butthe pipe 13 provides a passage for fluid cooling means for each beam aswell as for adjacent bricks 3 and fusion plates 19.

When the roof is installed each beam i is placed in position and securedin place by the bolts 25 at each end. For receiving the bolts 25, eachend of the beam preferably is provided with an angle member 26 having abolt slot 27 (FIG. 8) extending transversely to the axis of the beam 4.Bolt slots 23 are also provided in the upper flange 0f the channelmembers 3, which slots extend perpendicular to the slots 27 in the anglemembers 26. This arrangement of slots 27-28 permits the ends of the archbeams 4 to come and go incident to expansion and contraction of thebeams as the furnace is heated and cooled.

As shown in FIG. 7, the tubular portion 13 of the beams 4 may beconnected with a water coolant system by providing interconnectingconduits 29 at the rear ends of the beam 4; and by providing conduits3t} and 3-1 connected with the conventional water cooling means for anopen hearth door 32 and 'door frame 33. In the alternative, the pipe 13may be used as an air-conducting conduit for an air cooling systemrather than for a water cooling system.

Accordingly, the present invention provides a basic brick roofconstruction for open hearth furnaces that eliminates prior artdifficulties by providing means for not only holding up the brickseparately and individually but also for holding down each individualbrick and for preventing arch courses of basic brick from rising due toexpansion which occurs at elevated temperatures.

Shch means also includes the rigid arch beam, the opposite ends of whichare secured in place on opposite sides of the furnace. With each brickindividually attached to a beam and with the upper end surface of eachbrick in abutment with the undersurface of the beam, the bricks duringany tendency of expansion are maintained in their original position.Moreover, the means includes the fusion plates which not only dissipateheat from the surfaces of the bricks but also upon burn-off provideexpansion or swelling space for the flame exposed end portions of thebrick.

In addition, the arched beam may be provided with either water or aircooling means that may or may not be used in conjunction with thetypical water cooling system for the doors and door frames of openhearth furnaces.

Furthermore, the new basic brick roof construction provides for theinstallation of a new roof at a minimum of expense because of theelimination of the need for temporary forms for holding the bricks inthe proper arch location during erection, as well as the elimination ofthe need for skilled brick masons, because the improved construction maybe installed by relatively unskilled labor.

Other important aspects of the invention are the use of unnotched,metal-encased, wedged basic brick with hangers integral with the casing,and the cooperative relation thereof to the arch beams which hold eachbrick down and from which each brick hangs. The unnotched character ofeach brick provides a solid refractory body of maximum strength,eliminating the weakness introduced into the refractory material ofprior basic open hearth furnace roof brick by notches or cavities alwayspresent in prior constructions.

Further, since each brick is suspended through its casing and held downby top end abutment with the arch beam, the dead weight of each brick issupported by the wedge shape of its casing and not through the body ofthe refractory material itself. Thus each brick is supported and held infixed position in its arch course without introducing any tensionalstresses in the refractory body of the brick.

Also, during burn-off of the flame exposed ends of the brick, brickcasing material and fusion plates, and the complex reactions occurring,there may be some bonding, welding or fusion between any two or all ofthe refractory material, metal casing material and fusion plates, which,coupled with the wedge shape of each brick casing tend to hold therefractory material intact, even though some spalling or cracking of therefractory material may be initiated. These characteristics of theimproved construction, coupled with the space accommodation for swellingduring burn-off provided by the heavy metal fusion plates, result in aminimum of deterioration, spalling, cracking and dropping out ofrefractory material at the flame exposed surface of the roof during hightemperature furnace operation and heating and cooling periods.

The description of the improved open hearth roof construction is by wayof example and the scope of the invention is not limited to the exactdetails illustrated or to the specific sizes of brick, fusion plates androof shown, or to the particular refractory composition of the basicbrick described, since these details, sizes and composition may bevaried to suit the conditions or specifications of any particularfurnace involved.

Having now described the features, discoveries and principles of theinvention, the construction and operation of the new basic brick openhearth furnace roof, and the advantageous, new and useful resultsobtained thereby; the new and useful apparatus, constructions,arrangements, combinations, subcombinations, elements, parts, principlesand discoveries, and mechanical equivalents obvious to those skilled inthe art are set forth in the appended claims.

What is claimed is:

1. In an all basic furnace roof, a series of spaced bricksupporting andhold-down beams extending over the furnace and having opposite endssecured to opposite side walls of a furnace, a series of adjacentcourses of solid,

unnotched, basic material bricks, each brick having a metal casing forthe four sides of the basic material of said brick, the casing beingprovided at its upper end with at least one beam-engaging hook, the hookbeing secured directly to one of the beams, each hook projecting upwardfrom the side of the brick and being integral with the casing, each hookbeing .engageable with and disengageable from one side of the beam, theseries of courses of bricks being grouped in pairs of adjacent coursesin which all of the bricks of one pair of courses are secured to onebeam and all of the bricks in an adjacent pair of courses are secured toan adjacent beam, the bricks in one course of a pair of courses being inedge-to-edge surface abutment at one edge with edges of bricks in theadjacent course of the pair of courses, the bricks in said one coursealso being in edge to-edge surface abutment at another edge with edgesof bricks in another adjacent course of another pair of courses, eachbeam having an undersurface of substantial area extending in oppositedirections from a plane passing through said edge-to-edge surfaceabutment of bricks in a pair of courses, the upper end of each brick ineach course being engaged in suriface-to-surface abutment with theundersurface of the beam to which the brick is secured, and saidedge-to-edge surface abutment of the bricks in a course of one pair ofcourses with bricks in a course of another pair of courses holding saidbricks in hooked engagement with the beams to which the bricks aresecured, whereby each brick in every course is held down in position byits surface-to surface abutment with the undersurface of the beam towhich the brick is secured.

2. The construction defined in claim 1 in which the undersurface of eachbeam is in substantial horizontal alignment at any section with theundersur face of the adjacent beams.

3. In an all-basic furnace roof arch, a series of spaced archedbrick-supporting and holddown beams extending over the furnace andhaving opposite ends secured to opposite side walls of the furnace, aseries of arched courses of solid .unnotched basic material wedgebricks, each brick in any course having a metal casing for the foursides of the basic material of said brick, the casing being provided atits upper end with at least one beamengaging hook, each beam having acenter web portion and having flanges extending horizontally in oppositedirections from the web portion, said flanges having an undersurface ofsubstantial area, the beam-engaging hook of each brick being directlysecured to and on one side of a flange of the beam, the series ofcourses of bricks being grouped in pairs of adjacent courses in whichall of the bricks of one pair of courses are secured to one beam and allof the bricks in an adjacent pair of courses are secured to an adjacentbeam, the bricks in one course of a pair of courses being inedge-to-edge surface abutment at one edge with edges of bricks in theadjacent course of the pair of courses, the bricks in said one coursealso being in edge-to-edge surface abutment at another edge with edgesof bricks in another adjacent course of another pair of courses, theupper end of each brick in each course being engaged insurface-to-surface abutment with the undersurface of the beam to whichthe brick is secured, and said edge-to-edge surface abutment of thebricks in a course of one pair of courses with bricks in a course ofanother pair of courses holding said bricks in hooked engagement withthe flanges, where- 1 1 by each course of bricks is held down in placeagainst upward movement by the beam during furnace operation.

4. In an all-basic furnace root, a series of spaced brick hold-downbeams extending over the furnace and having opposite ends secured toopposite side Walls of a furnace, a series of adjacent courses of solid,unnotched, basic material bricks, each brick having a metal casing forthe four sides of the basic material of said brick, the series ofcourses of bricks being grouped in pairs of adjacent courses, the bricksin one course of a pair of courses being in edge-to-edge surfaceabutment at one edge with the edges of bricks in the adjacent course ofthe pair of courses, the bricks in said one course also being inedgeto-edge surface abutment at another edge with edges of bricks inanother adjacent course of another pair of courses, each brick in agiven course having a beam-engaging hook extending above and integralWith the easing and being engageable with and disengageable from oneside of the beam, each beam having an undersurface of substantial areaextending in opposite directions from a plane passing through saidedge-to-edge surface abutment of bricks in a pair of courses, the upperend of each brick in each course being engaged in surface-.to-surfaceabutment with the undersurface of its corresponding 12 beam, and saidedge-to-edge surface abutment of the bricks in adjacent courses holdingthe bricks in lateral alignment with their corresponding beams, wherebyeach brick in every course is held down in position by its surtace-to-surface abutment with the undersurface of its correspondingbeam.

References Cited in the file of this patent UNITED STATES PATENTS1,463,240 Biglow July 31, 1923 1,472,945 Strachota Nov. 6, v19231,896,769 Davis et a1 Feb. 7, 1933 1,948,093 Baird et al Feb. 20, 19342,781,006 Heuer Feb. 12, 1957 2,930,601 Heuer Mar. 29, 1960 2,932,265Heuer Apr. 12, 1960 3,005,423 Longenecker Oct. 24, 1961 3,005,424:I-Ieuer Oct. 24, 1961 FOREIGN PATENTS 523,620 Italy Apr. 18, 1955938,265 Germany Jan. 26, 1956 1,014,200 France 'May 28, 1952 1,072,449France Mar. 17, 1954 1,187,813 France Mar. 9, 1959

1. IN AN ALL BASIC FURNACE ROOF, A SERIES OF SPACED BRICKSUPPORTING ANDHOLD-DOWN BEAMS EXTENDING OVER THE FURNACE AND HAVING OPPOSITE ENDSSECURED TO OPPOSITE SIDE WALLS OF A FURNACE, A SERIES OF ADJACENTCOURSES OF SOLID, UNNOTCHED, BASIC MATERIAL BRICKS, EACH BRICK HAVING AMETAL CASING FOR THE FOUR SIDES OF THE BASIC MATERIAL OF SAID BRICK, THECASING BEING PROVIDED AT ITS UPPER END WITH AT LEAST ONE BEAM-ENGAGINGHOOK, THE HOOK BEING SECURED DIRECTLY TO ONE OF THE BEAMS, EACH HOOKPROJECTING UPWARD FROM THE SIDE OF THE BRICK AND BEING INTEGRAL WITH THECASING, EACH JOOK BEING ENGAGABLE WITH AND DISENGAGEABLE FROM ONE SIDEOF THE BEAM, THE SERIES OF COURSES OF BRICKS BEING GROUPED IN PAIRS OFADJACENT COURSES IN WHICH ALL OF THE BRICKS OF ONE PAIR OF COURSES ARESECURED TO ONE BEAM AND ALL OF THE BRICKS IN AN ADJACENT PAIR OF COURSEARE SECURED TO AN ADJACENT BEAM, THE BRICKS IN ONE COURSE OF A PAIR OFCOURSES BEING IN EDGE-TO-EDGE SURFACE ABUTMENT AT ONE EDGE WITH EDGES OFBRICKS IN THE ADJACENT COURSE OF THE PAIR OF COURSES, THE BRICKS IN SAIDONE COURSE ALSO BEING IN EDGE-TO-EDGE SURFACE ABUTMENT AT ANOTHER EDGEWITH EDGES OF BRICKS IN ANOTHER ADJACENT COURSE OF ANOTHER PAIR OFCOURSES, EACH BEAM HAVING AN UNDERSURFACE OF SUBSTANTIAL AREA EXTENDINGIN OPPOSITE DIRECTIONS FROM A PLANE PASSING THROUGH SAID EDGE-TO-EDGESURFACE ABUTMENT OF BRICKS IN A PAIR OF COURSES, THE UPPER END OF EACHBRICK IN EACH COURSE BEING ENGAGED IN SURFACE-TO-SURFACE ABUTMENT WITHTHE UNDERSURFACE OF THE BEAM TO WHICH THE BRICK IS SECURED, AND SAIDEDGE-TO-EDGE SURFACE ABUTMENT OF THE BRICKS IN A COURSE OF ONE PAIR OFCOURSES WITH BRICKS IN A COURSE OF ANOTHER PAIR OF COURSE HOLDING SAIDBRICKS IN HOOKED ENGAGEMENT WITH THE BEAMS TO WHICH THE BRICKS ARESECURED, WHEREBY EACH BRICK IN EVERY COURSE IS HELD DOWN IN POSITION BYITS SURFACE-TOSURFACE ABUTMENT WITH THE UNDERSURFACE OF THE BEAM TOWHICH THE BRICK IS SECURED.